1. Field of the Invention
The present invention relates to a wireless communication system and more particularly, to a method of sharing a frequency between the same or different wireless communication systems.
2. Description of the Related Art
Unlike licensed bands, in unlicensed bands, systems employing different communication schemes may share and use the same frequency. For example, industrial, scientific and medical (ISM) bands are being mainly shared and used by a wireless local area network (WLAN) system and a Bluetooth system. To avoid a frequency collision with a WLAN, a scheme of generating and using only good frequencies as a hopping sequence during a frequency hopping is being used in a Bluetooth wireless communication scheme. The above scheme may be advantageous to both the Bluetooth and a wireless fidelity (WiFi) in terms of a transmission rate.
However, the above scheme may be possible due to specificity of a Bluetooth modulation scheme of performing a frequency hopping in a relatively wide band of 79 megahertz (MHz). The above adaptive frequency hopping scheme may not be available in all communication schemes. In a 3rd Generation Partnership Project (3GPP) system, for example, a long-term evolution (LTE), a single serving cell has 20 MHz, which is similar to a size of a band used in the WLAN. Accordingly, it may be difficult to perform a communication in bands other than the band used in the WLAN, when the same central frequency is used by the 3GPP system and the WLAN.
Therefore, there is a desire for a coexistence method to enable a communication system operating in a bandwidth similar to that of a WLAN system to coexist with the WLAN system in an unlicensed band, in a different manner from a case of a Bluetooth system.